Refer to FIG. 1. FIG. 1 is a circuit diagram showing a power switch of a conventional electric device. Conventional technology uses a latch type switch 12 to determine if a power supply voltage 14 is provided to an electric device 16. However, latch type switches are more expensive than normal electric switches, such as a transistor switch, and the latch type switch cannot buffer the power supply voltage. When the latch type switch is turned on, the power supply voltage 14 is immediately provided to the electric device 16, thereby leading to current spike effect.
Therefore, a new, cheaper switch circuit with a buffer function is required.